1. Field of the Invention
This invention relates to corrosion inhibiting compositions for metals and more particularly to such compositions for silicon iron and other steels.
2. Description of the Prior Art
Atmospheric corrosion inhibitors offer an excellent method of protecting metallic objects against the aggressive effects of hostile environments without much concern in regard to shape or size of the object to be protected. The method of application is either by spraying the inhibitor onto the surface or immersion of the part in a bath of the inhibitor formulation.
Corrosion protection is offered by partial or complete inhibition of the electrochemical reactions leading to the degradation of the metallic elements. Several excellent corrosion inhibitors are commercially available that can be used on iron and steel parts for general purpose applications. These are usually complex mixtures and may contain one or more trace quantity constituents which are critical to an effective protection.
When materials in different process steps require complete removal of the inhibitor, a knowledge of the composition of the inhibitor formulation is essential for satisfactory removal of the protective film with an appropriate solvent system.
The prior art such as U.S. Pat. No. 4,130,524 does broadly teach the combination of an amine and an acid to form a salt which is a barrier to corrosive elements. However, in the present invention a glycol ester and an organotin compound are included to enhance the action of the acid and amine. Also, the compositions of the present invention are totally homogeneous. The present invention is oil based whereas the compositions of U.S. Pat. No. 4,130,524 are water based. Diffusion through the aqueous base could occur and corrosion could accelerate. Even though the compositions of the present invention are oil based, they are easily removed using commercial solvents such as methyl chloroform.